To answer received questions about scale, signs and example data
(In time an instruction text will appear on the FTP SITE):
To show imaging by a biconvex lens of f = 10 (arbitrary
units) of an object plane at 2f (paraxial image also at 2f):
1.) To define the optical system (including the input & output planes):
In the first screen ("Configuration") enter the numbers:
First row of "boxes": 1 20 10 8
Second row : 1.5 2 -10 8
Third row : 1 30 leave all other "boxes"
blank, then =>
2.)To show a fan of 5 rays emanating from each of 5 object points:
click on "ADD RAY(S)" and enter, in the new screen, the numbers:
In the Row "RAY HEIGHT": 0 1 -1 2 -2
In the Row "RAY ANGLE": 0 1 -1 2 -2
Choose "degrees"
Enter a "VERTICAL MAGNIFICATION" of 4
Click "OK"
Click "HIDE CONTROLS" for a clear view (click anywhere to restore
controls). Note the aberrations! What you see are the ray tracings as
predicted by Snell's law and perfectly spherical interfaces, with no
approximations.
The "Configuration" entries specify the index of refraction, length, and
terminating interface of three segments:
1.) 20 units of n=1 (air), terminated by an R = +10 units interface whose
vertical aperture is 8 units
2.) 2 units of n=1.5 (glass), terminated by an R -10 units interface
whose vertical aperture is 8 units
3.) 30 units of n =1 (air).
(Read the blurb on the "Configuration" screen for more details.)
You may go back and forth among the screens (and change data) by using
the "drop down" VIEW menu, or the "taskbar" of WIN95.
Exit the program by clicking on QUIT of any screen.
The horizontal scale is fixed so that the horizontal screen width (40
grid squares) always represents the sum of all of the (necessarily
positive) lengths which you entered in column 2 of the Configuration
screen. By default, this is also the vertical scale. The vertical scale
can be changed by entering a Vertical Magnification unequal to 1 in the
Add Rays screen; this will not affect the recorded numerical data, only
the (vertical) screen scale.
Light is presumed to go from left to right; ray angles are positive for
upward directions, negative for downward directions; Radii of interfaces
are positive if the center of curvature lies to the right of the vertex
(convex => opening to the right), negative otherwise (concave => opening
to the left).
All of these conventions are best illustrated by referring to their
application in the above data for the biconvex lens.
In time, I will be posting data for other configurations (eg the Cook
Triplet) on the FTP Site.